Its important to remember that everyones contribution, no matter how small, is essential to the team's success.
Correct: A
The phrase 'Its important' should be 'It's important', which is a contraction of 'it is'. The word 'everyones' should be 'everyone's', indicating possession ('the contribution of everyone'). Option A correctly applies both apostrophe rules. Options B, C, and D contain errors in contractions or possessives.